Am I damaging my Suburban by towing with it?

[ROBERT CROSS]

Originally Posted by dznf0g

I still say try it the way it is and see if it is comfortable for YOU, performance wise. There's plenty of time later to swap out gears (yes, 2 sets!)

If you were trying to pull a 30'er or a 34'er, I'd be much more concerned about durability, etc. Not so much with a 25'er.

X2

Bob

[phbarnhart]

@ dznf0g and Bob: That's kind of why I'm doing this now. I did a 2000 mile trip from Eugene, OR to Helena, MT (plus a some around Montana) trip in October before I put her to bed for the winter. What I learned from the trip is that there's a very good reason that the tow package comes with the 3.42 gearing; it's only a little bit lower, but a little bit seems like all that would be needed to keep the transmission from shifting all the time, even while cruising.

I do appreciate the advice though, basically, if I may paraphrase, you're saying that I'm not really hurting anything by towing with the 3.08 but I may be more comfortable with the 3.42 or 3.73 so it's basically a judgement call about the cost v. my personal towing comfort.

[tpi]

I'd tow it around a bit before jumping on a 9 percent change in ratio. Off the top of my head it doesn't seem like enough of a change to warrant the expense (and possible reliability hit due to improper setup) to change two differentials.

Once you've towed with the stock setup, you'll be in a better position to determine just what it needs. My guess is if needs to be changed it will need to go to 3.73 or 4.11.

[dznf0g]

Originally Posted by phbarnhart

@ dznf0g and Bob: That's kind of why I'm doing this now. I did a 2000 mile trip from Eugene, OR to Helena, MT (plus a some around Montana) trip in October before I put her to bed for the winter. What I learned from the trip is that there's a very good reason that the tow package comes with the 3.42 gearing; it's only a little bit lower, but a little bit seems like all that would be needed to keep the transmission from shifting all the time, even while cruising.

I do appreciate the advice though, basically, if I may paraphrase, you're saying that I'm not really hurting anything by towing with the 3.08 but I may be more comfortable with the 3.42 or 3.73 so it's basically a judgement call about the cost v. my personal towing comfort.

Yes, that's exactly what I am saying. You could always manually select a gear to prevent hunting. I have done that for years on the older 4 speeds. Sure, it may cost a little in fuel, but think about how much difference in economy will cost compared to swapping.

I would probably do some minor mods to the truck. I think the trans cooler was discussed upthread. For the axle, you might want to get a cast aluminum performance diff cover. It is finned and cools the axle lube better and it increases capacity. I'd also investigate some heavy duty performance full synthetic axle lube. Your truck was factory filled with a full syn fluid, but it was designed primarily for long life (maintenance reduction) and fuel economy (flows better).

Unless you just can't stand it.

Sorry, I missed that you already had some towing experience with this rig.

[ROBERT CROSS]

Now we're get'n sum place.

Bob

[phbarnhart]

Originally Posted by dznf0g

Yes, that's exactly what I am saying. You could always manually select a gear to prevent hunting. I have done that for years on the older 4 speeds. Sure, it may cost a little in fuel, but think about how much difference in economy will cost compared to swapping.

I would probably do some minor mods to the truck. I think the trans cooler was discussed upthread. For the axle, you might want to get a cast aluminum performance diff cover. It is finned and cools the axle lube better and it increases capacity. I'd also investigate some heavy duty performance full synthetic axle lube. Your truck was factory filled with a full syn fluid, but it was designed primarily for long life (maintenance reduction) and fuel economy (flows better).

Unless you just can't stand it.

Sorry, I missed that you already had some towing experience with this rig.

Wow, I never knew that there were so many different little towing performance modifications available! I can see how this "hobby" could get expensive.

Oh, and I do manually select the gear, especially when going through hilly parts, and not just when towing.

[phbarnhart]

Originally Posted by ROBERT CROSS

Now we're get'n sum place.

Bob

I know, and it ONLY took four pages of posts! That's gotta be a new record around here!

[ROBERT CROSS]

Originally Posted by phbarnhart

I know, and it ONLY took four pages of posts! That's gotta be a new record around here!

Best of luck, let me guess...Phil.

Get the "little" stuff done, I think you'll be able to realize some significant improvements.

Bob

[slowmover]

I've yet to find someone upset with gear changes for towing. Fuel mileage on the highway is about it. While 3.7 may be more than the "needed" 3.4 the difference will always be less drivetrain strain. A 4000-rpm torque peak is more easily reached, gear-by-gear, with numerically higher axle gears. Less strain = less heat = longer life (potentially). Vehicle responsiveness is worlds better.

All the other changes (book or better maintenance intervals, filters, gauges, etc) are a good idea on any auto-trans vehicle. (And an AUTOMETER vacuum gauge is a good way to learn to shift for upgrades). And while the "performance aftermarket" will make a truck [man] faster, stronger [and stiffer] the truth is nothing equals a drive gear set for performance. And this isn't a slow-turning big V8, either.

On my TD truck the 3.7 gearset is a ideal blend of performance versus economy. But I won't be towing any 15k trailers. So a planned change will be to the 3.4 gearset. This will put my cruise rpms -- city or country -- nearer the sweet spot for FE. And it wouldn't bother me to change them back or go higher if it was warranted. This would be better than playing with tires (since that also affects braking, handling, etc). A bit slower up the mountains is an irrelevant concern as I'm already overpowered (in the ways that engine power numbers don't always reveal).

3.7 gears (or a tire change) will suck the fuel, no question about it. Solo cruising at 70-mph (already dumb when in a truck) will need to come down to 65 or so (and get there just as "fast"). Same for towing. Have to be more careful in wet conditions. Etc.

The OP will do what he wants, but as his portion of the country has several mountain ranges in any conceivable direction (thus altitude problems as well for an N/A engine), better gearing is pretty simple as a "solution". If he lived in Florida and drove to the Catskills annually then the 3.0 "dilemma" might be different. But some of the worst grades in the country are within two days travel of the OP's home.

If we can ever get him to nail the hitch rig numbers on a scale then the performance changes all around will make him a believer. A year or two from now will be a bigger trailer and a better spec'd TV.

.

[phbarnhart]

Originally Posted by REDNAX

I've yet to find someone upset with gear changes for towing. Fuel mileage on the highway is about it. While 3.7 may be more than the "needed" 3.4 the difference will always be less drivetrain strain. A 4000-rpm torque peak is more easily reached, gear-by-gear, with numerically higher axle gears. Less strain = less heat = longer life (potentially). Vehicle responsiveness is worlds better.

All the other changes (book or better maintenance intervals, filters, gauges, etc) are a good idea on any auto-trans vehicle. (And an AUTOMETER vacuum gauge is a good way to learn to shift for upgrades). And while the "performance aftermarket" will make a truck [man] faster, stronger [and stiffer] the truth is nothing equals a drive gear set for performance. And this isn't a slow-turning big V8, either.

On my TD truck the 3.7 gearset is a ideal blend of performance versus economy. But I won't be towing any 15k trailers. So a planned change will be to the 3.4 gearset. This will put my cruise rpms -- city or country -- nearer the sweet spot for FE. And it wouldn't bother me to change them back or go higher if it was warranted. This would be better than playing with tires (since that also affects braking, handling, etc). A bit slower up the mountains is an irrelevant concern as I'm already overpowered (in the ways that engine power numbers don't always reveal).

3.7 gears (or a tire change) will suck the fuel, no question about it. Solo cruising at 70-mph (already dumb when in a truck) will need to come down to 65 or so (and get there just as "fast"). Same for towing. Have to be more careful in wet conditions. Etc.

The OP will do what he wants, but as his portion of the country has several mountain ranges in any conceivable direction (thus altitude problems as well for an N/A engine), better gearing is pretty simple as a "solution". If he lived in Florida and drove to the Catskills annually then the 3.0 "dilemma" might be different. But some of the worst grades in the country are within two days travel of the OP's home.

If we can ever get him to nail the hitch rig numbers on a scale then the performance changes all around will make him a believer. A year or two from now will be a bigger trailer and a better spec'd TV.

.

You faith in me is probably misplaced... however, I do have a family trip to the scales planned. ;-)

Your right about the mountains surrounding me. Are you thinking that I should go with the 3.73?

[phbarnhart]

Originally Posted by ROBERT CROSS

Best of luck, let me guess...Phil.

Get the "little" stuff done, I think you'll be able to realize some significant improvements.

Bob

Thanks, and, you're right, it's Phil.

[slowmover]

The 3.08's will get the job done. But will you be one of the sheeple afraid to climb mountain passes at slower speeds. Will elevated trans temps (but not to a severe point) bother you?

- How long will you keep the TV?

- How many miles towing in that time?

- How many nights in use for the TT in that time?

Every TV that is not a turbodiesel is simply somewhere farther down the scale of overall performance (a DI turbocharged gas motor [a la EcoBoost] being second), so just how important is it to you?

I'd rate trailer disc brakes, VPP hitch, MAXBRAKE controller and perfect dial-in of both as higher on the scale of, "What's important".

A gear change is simple, IMO. But the truck will be different, and the lower fuel economy while solo may tick you off. Sure as hell will accelerate though. You can tick off a few greenies.

Answer the questions above, as only the OP can figure the relation of money and satisfaction. Work the numbers, first.

That said, my parents used a '76 Cadillac with 3.2 gears and traveled over 187,000-miles in the first [12] of [27] years of ownership of their '28 7k Silver Streak out of Texas and all over creation. They liked the next TV better . . but only as a TV, not so much when solo.

I'd do the gears after the other items I mentioned above. And last year. They're indisputably superior. And permanent. The gears are just for fun (and some peace of mind). I doubt you'll have this TV very long anyway. So enjoy it.

You want an 1187 Remington off the pawn shop rack . . or a fitted Beretta? You can trick out the former all day as it is better start there and have an idea of what's best for you.

.

[phbarnhart]

Great, thanks for the advice... again... I'm planning on getting a quote on disk brakes from Sutton RV, I've got a Tekonsha P3 brake controller that seems to work pretty well, and the VPP hitch is also in the works.

[phbarnhart]

Update: The indy shop that I was talking to wants $5900 to do the gearing swap. No. Flippin'. Way.

If I'm going to spend that kind of $$$ I might as well buy a new TV.

[starcraft]

It's a suburban if it is not built to haul 8 people I do not know what is. Your axle ratio is fine without hills involved. From my jeeping day's 3.07s came with many jeeps with 4.0 liter motor. I ran 33inch tires not the greatest setup at all lowers rpms quite alot. Next offering 3.55s and made it more doable with those size tires. 3.73s came later on and 4.11s offered on 4cyls but so doggy it did not mater. So you have to go slow on hills big deal. Just make sure you do not put larger tires on rig if you plan on towing. May want to stay out overdrive on big hills and turn air off. Going down hills you will be getting better mileage with tall gearing maybe even on flats with no wind. My issue now is my Nissan is over geared to compete with Toyota Tacoma 4.65s something like that. My rpms are to high for mileage but yeah it will pull, wish I had another gear to shift into like 6th. Another factor is tranny gear ratios. If you really must have new gears try 4wheel parts would think $1000 an axle should get it done. If Suburban has front axle lol being Chev I doubt it, may be more complicated and expensive for your front 4x4. 2wd should be pretty cheap.

[ROBERT CROSS]

[QUOTE=phbarnhart;1117723]Update: The indy shop that I was talking to wants $5900 to do the gearing swap. No. Flippin'. Way.


OUCH!!

Full speed ahead, well maybe not full.. speed....

As some advised so many posts ago, give 'er a try, don't overload the TV axle's and tires, get a temp gauge/filter for the tranny. Maybe do a tranny flush & fill just for S&G's.

Good Luck...

Bob

[Alumaholic]

Originally Posted by phbarnhart

Update:

If I'm going to spend that kind of $$$ I might as well buy a new TV.

By jove, I think you've got it!

[phbarnhart]

ProPride hitch ordered and I've asked for a quote to install disc brakes on the AS. I figure no matter what else happens with my TV choice I'll want those two things.

[slowmover]

Originally Posted by phbarnhart

ProPride hitch ordered and I've asked for a quote to install disc brakes on the AS. I figure no matter what else happens with my TV choice I'll want those two things.

Couldn't agree more that the TT is the permanent possession by comparison to TV's that can come and go.

And, as it is an A/S the literal range of TV's thus makes bettering the TT -- and, by extension, the TV -- a more capable vehicle in pairing. It's a two way street that both are improved by a VPP hitch and TT disc brakes.

Good news.

.

[phbarnhart]

Update: I caved. I'm picking up the 3/4 ton Suburban on Saturday.